Integration of Magnetic Phase-Change Microcapsules with Black Phosphorus Nanosheets for Efficient Harvest of Solar Photothermal Energy

Abstract

Solar photothermal energy storage using phasechange material (PCMs) provides sustainable penetration in comprehensive utilization. However, PCMs are obliged to suffer from low conversion and storage effectiveness in solar photothermal energy due to a low optical absorption capacity. In this study, we developed a type of magnetic phase-change microcapsule system with superior photothermal energy conversion efficiency. The microcapsule system was constructed with n-docosane as a PCM core and a CaCO 3 /Fe 3 O 4 composite shell surface-decorated with black phosphorus (BP) nanosheets employing a Pickering emulsion-templated precipitation technique. The presence of BP nanosheets on the capsule surface not only enhanced the emulsion stability to facilitate the fabrication of a tight CaCO 3 -based shell, resulting in a high latent heat capacity of the microcapsules, but also improved thermal conduction of the microcapsule system, promoting a fast thermal response and heat transfer. The microcapsule system shows a high phase-change enthalpy of over 120 J/g and a significant increase in thermal conductivity by over 400% compared to pure PCM. More importantly, the microcapsule system exhibits a high photothermal conversion efficiency of 95.08%, which is superior to most of the PCM-based composite materials reported in the literature. There is only 0.02% conversion efficiency lost after the 10-cycle photothermal conversion experiment for the microcapsule system, indicating a good working stability for the long-term use of solar photothermal conversion and storage. By decorating magnetic phase-change microcapsules with BP nanosheets on the shell, this study offers a new strategy for development of PCM-based composite materials for efficient harvest and utilization of solar energy. KEYWORDS: magnetic phase-change microcapsules, black phosphorus nanosheets, CaCO 3 /Fe 3 O 4 composite shell, core-shell structure, photothermal conversion efficiency, thermal energy storage

Engineering Materials to Enhance Light-to-Heat Conversion for Efficient Solar Water Purification

“…They also showed good thermal resistance and high thermal cycle stability. To resolve the leakage problem during the phase transition from solid to liquid that results in poor cycle stability and durability of PCMs, Liu’s group microencapsulated the PCMs with CaCO 3 /Fe 3 O 4 composite shells. − CaCO 3 is considered to be suitable as a wall of material for the microencapsulation of PCMs because it has a rigid and tight nature, high thermal conductivity, low cost, and requires mild synthetic condition. To achieve high solar–thermal-conversion efficiency, Fe 3 O 4 nanoparticles, that have an ability to accelerate photothermal energy conversion and storage, were incorporated.…”

Phase Change Composite with Core–Shell Structure for Photothermal Conversion and Thermal Energy Storage

“…The MSR thin layer shelters PCM from leakage above its melting point and also provides the PCC with outstanding thermal reliability. By comparing with the relevant work, our work creates a novel assembly form to prepare functional macroencapsulated PCCs, which allows the uniform and spatial distribution of PCMs and photothermal conversion particles, guaranteeing the relatively high photothermal conversion capacity and exothermic accuracy of composites. − In general, PCM@PUF-CuS@MSR is a cheap, difunctional, and macroencapsulated PCC with a core–shell structure which is acquired from MPCMs, demonstrating great potential as an energy storage medium for low-temperature solar energy storage, such as domestic solar water heaters, photothermal cells based on PCMs, and so on. , …”

CuS Nanoparticle-Based Microcapsules for Solar-Induced Phase-Change Energy Storage

“…In fact, copper sulfide has been used in PCM microcapsules to prepare solar energy conversion and storage PCM microcapsules by filling CuS nanoparticles into the PCMs or shell . Several other studies also reported solar-driven energy storage microcapsules prepared by surfactant-stabilized emulsion with CNTs, Fe 3 O 4 , PDA, or black phosphorus as photothermal materials. These nanoparticles were integrated into the shell of the PCM microcapsules as photothermal conversion functional fillers.…”